Submersible mixer



FIG. 1 is a right side elevational view of a submersible mixer showing my new design;

FIG. 2 is a left side elevational view;

FIG. 3 is a bottom plan view;

FIG. 4 is a top plan view;

FIG. 5 is a front elevational view; and

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a submersible mixer, as shown and described. 